Separation of quadrupolar and paramagnetic shift interactions with TOP‐STMAS/MQMAS in solid‐state lighting phosphors

Carvalho, José P.; Jaworski, Aleksander; Brady, Michael; Pell, Andrew J.

doi:10.1002/mrc.5004

Cited by 11 publications

(9 citation statements)

References 62 publications

(139 reference statements)

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“…Al resonances upon incorporation of Ce (or other paramagnetic lanthanides) in Y3Al5O12 (YAG),[29][30][31] as well as for43 Ca and45 Sc NMR signals from CaSc2O4 doped with Ce 32. However, the assessment on δcon/δpc mechanisms could not be established.…”

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confidence: 99%

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Ma¹,

Dronskowski²,

Slabon³

et al. 2020

Preprint

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14N magic-angle spinning (MAS) NMR spectra of diamagnetic LaTiO2N perovskite oxynitride and its paramag- netic counterpart CeTiO2N are presented. The latter, to the best of our knowledge, constitutes the first high-resolution 14N MAS NMR spectrum collected from paramagnetic solid material. Induced paramagnetic 14N NMR shift due to unpaired 4f -electrons in CeTiO2N is non-existent, which is remarkable given the severe paramagnetic effects on surface proton species revealed by 1H NMR, and direct Ce−N contacts in the structure. Ab initio molecular orbital calculations predict substantial Ce→14N contact shift interaction under these circumstances, therefore, cannot explain the unprecedented 14N NMR spectrum of CeTiO2N.

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confidence: 99%

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Ma¹,

Dronskowski²,

Slabon³

et al. 2020

Preprint

Self Cite

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“…The shift interaction provides information about the chemical environment, bonding geometry and delocalisation/polarization of the spin density via the hyperfine interaction, 49,50 whereas the quadrupole interaction is very sensitive to the local lattice and coordination geometry and dynamics on the μs–ms time scale. 51–53 The recently reported 2D adiabatic shifting d -echo experiment 40 can separate and correlate the two interactions as shown in Fig. 3, which allows a very accurate evaluation of the tensor parameters.…”

Section: Resultsmentioning

confidence: 98%

Probing the electronic structure and hydride occupancy in barium titanium oxyhydride through DFT-assisted solid-state NMR

Aleksis

Nedumkandathil

Papawassiliou

et al. 2022

Phys. Chem. Chem. Phys.

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“…These are called anisotropic bulk magnetic susceptibility (ABMS) effects. [26][27][28] The significant spin-orbit coupling, and therefore substantial anisotropy of the magnetic susceptibility of the Ni 2+ ion combined with the strongly anisotropic shape of nanodomains in the Al-doped (x = 0.10) sample are expected to result in a particularly pronounced ABMS effects.…”

Section: Nmr Resultsmentioning

confidence: 99%

Exploring the Nanoscale Origin of Performance Enhancement in Li_1.1Ni_0.35Mn_0.55O₂ Batteries Due to Chemical Doping

Thersleff

Biendicho

Prakasha

et al. 2023

Advanced Energy Materials

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While cathode materials with a layered structure containing Co such as LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111) can currently provide high capacities, their use for next-generation Li-ion batteries is limited by the high toxicity, cost, and ethical issues associated with cobalt mining. [3,4] Due to the strategic importance of Co reduction or elimination, a wide range of alternative compounds and lithium chemistries are currently being researched; [5] however, most of these exhibit significant drawbacks compared to NMC111. For example, olivine (LiFePO 4 ) [6] and spinel (LiNi 0.5 Mn 1.5 O 4 ) [7] based materials have interesting properties such as being Co-free, low cost and presenting high C-rate performance for rapid battery charging, but their capacity is limited to <200 mAhg −1 . Ni-rich layered oxides with low cobalt content, for example, LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) deliver high energy densities but suffer from slow kinetics and poor cycling stability requiring complex engineering at the particle level to enhance performance. [8,9] Additionally, these materials are prone to reactivity and instability upon exposure to ambient conditions [10] and their price has increased lately.In addition to the aforementioned compounds, it is also possible to fabricate Co-free cathode materials based off the layered Li-Mn-rich oxides. These form complex nanocomposite structures due to their nanoscale integration of two structural components: a monoclinic C2/m Li 2 MnO 3 -like phase (M-phase) and a rhombohedral R-3m LiMn 1/2 Ni 1/2 O 2 -like phase (R-phase). [11,12] The presence of both structures as a nanocomposite material is desirable, as they differ in their cation ordering and are active at different potentials up to 4.6 V versus Li + /Li, thereby maximizing energy density. However, without the inclusion of Co, these nanocomposites show limited capacity retention, poor efficiencies, severe voltage fade, and a failure to deliver capacity at high C-rates. [13,14] Several approaches have been discussed in the literature to improve the performance of this system, and some of the most promising results have been obtained by chemical doping. [13,15,16] For instance, Al-doped samples showed superior cycling performance and lower voltage decay than parent compositions, [17][18][19] which was attributed to a robust R-phase stabilizing the overall structure while blocking the random growth of spinel-like phases. [17] The effect Despite significant potential as energy storage materials for electric vehicles due to their combination of high energy density per unit cost and reduced environmental and ethical concerns, Co-free lithium ion batteries based on layered Mn oxides presently lack the longevity and stability of their Co-containing counterparts. Here, a reduction in this performance gap is demonstrated via chemical doping, with Li 1.1 Ni 0.35 Mn 0.54 Al 0.01 O 2 achieving an initial discharge capacity of 159 mAhg −1 at C/3 rate and a corresponding capacity retention of 94.3% after 150 ...

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Separation of quadrupolar and paramagnetic shift interactions with TOP‐STMAS/MQMAS in solid‐state lighting phosphors

Cited by 11 publications

References 62 publications

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Probing the electronic structure and hydride occupancy in barium titanium oxyhydride through DFT-assisted solid-state NMR

Exploring the Nanoscale Origin of Performance Enhancement in Li_1.1Ni_0.35Mn_0.55O₂ Batteries Due to Chemical Doping

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Separation of quadrupolar and paramagnetic shift interactions with TOP‐STMAS/MQMAS in solid‐state lighting phosphors

Cited by 11 publications

References 62 publications

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Paramagnetic 14N MAS NMR without Paramagnetic Shifts: Remarkable Lattice of LaTiO2N and CeTiO2N Oxynitride Perovskites

Probing the electronic structure and hydride occupancy in barium titanium oxyhydride through DFT-assisted solid-state NMR

Exploring the Nanoscale Origin of Performance Enhancement in Li1.1Ni0.35Mn0.55O2 Batteries Due to Chemical Doping

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Exploring the Nanoscale Origin of Performance Enhancement in Li_1.1Ni_0.35Mn_0.55O₂ Batteries Due to Chemical Doping